Automatic starting system for internal-combustion engines



April 15, 1952 Filed Feb. l, 1945 M. P. ODE AUTOMATIC STARTING SYSTEMFOR INTERNAL-COMBUSTION ENGINES 2 SHEETS-SHEET l 521ML #ffy PatentedApr. 15, 1952 AUTOMATIC' STARTING SYSTEM FOR INTERNAL-COMBUSTIONENGINES' Malcolm. P. Odell, Minneapolis, Minn.,A assignor toMinneapolis-Honeywell Regulator Company,

Minneapolis,

Minn., a corporation of. Delaware Application February l, 1945',Scrial'No. '575,683

lliClaims. 1

This invention relates to a system. for starting the engines of anaircraft or'other internal combustion engines, requiring no attentionfrom thel pilot other than momentary pressurel or a starting switch,thus leaving him freel to perform other functions preliminary to taking;oflf the craft while the starting cycleV of thel engine is proceedingautomatically.

One object of the invention is toprovide a system which is automatic inall respects as far as starting of the engine is concerned and whichincludes thermostaticmeans responsive to the temperature ambient to theengine for setting into operation proper priming means, for starting theengine in asatisfactory mannen regardless of the prevailing temperature.

Another obj ectA is tuprovide, a. sequential timer for timing varioussteps in theA startingcycle such as the operation of an auxiliary fuelpump, al starter` for the engine, an ignition intensifier, and automaticpriming means, as well as means for meshing the starter at the propertime and furnishing a signal to the operator to indicate termination ofthe starting cycle.

Still another object isV to provide an automatic system wherein athermostat responsive to the temperature ambient to the engine energizesvarious combinations of relays, depending upon whether the temperatureisA high enoughthat no priming is required or low enoughthat priming isrequired, certain lower ranges of temperature positioning the thermostatso that aspecialauxiliary fuel can be used for priming the engineinstead of the regular engine fuel.

A further object is to provide a pump for the auxiliary priming fuelhaving a pressure setting arrangement which is controlled by relays foreither high or low pressure output, depending upon whether thetemperature is below a predetermined point such as degrees, or abovethat point.

Still a further object is toprovide a means to terminate the operationofv the various elements of the starting system after a timed period, orprior to that time provided the engine starts properly, so that there isno chance of the engine becoming ilooded.

An additional object is to provide a stop. control for the startingsystem which can be man.- ually operated at any time .during thestarting cycle in case the operator for any*v reason wishes to terminatethe starting cycle.

With these and other objects in view, my invention consists theelementsl of a starting system and their arrangementand combination (Cl.12S-187.5)

whereby the objects contemplated are attained, as hereinafter more fullyset forth, pointed out inthe claims and illustrated in theaccompanyingdrawings, wherein:

llig.4 1 is an electro-diagrammatic View of an automatic starting systemfor internal combustionv engines embodyingmy invention;

Fig. 2 isa diagram showing the circuits which come vinto play during thestartingV cycle and the timingfor the various circuits;

Fig.: 3, is adiagram showing the priming of the engine with differentfuels at various temperatures* and atv different pressures for certaintemperature ranges.; and

Fig. 4 is a detail View of a thermostat used in myesystem.

On the accompanying drawings I have used the referencey characterli toindicate an engine of,v internal combustion type, such as an aircraftengine. The engine E is provided with a starter S, such as oneof theusual inertia type, having a; ground terminal Il common tov tivocircuits, one of; which is energized through terminal Il andcontrolsthe; rotation of the starter and the other of which is energizedthrough terminal I3 and controls the engagement ofV the starter withengineE.

The; engine has an ignition intensifier or booster IB for the purpose ofproviding an eXtra hotl Spark. during the starting period, and this.`booster isA of conventional design. Fuel is supplied' to the engine Ethrough a carburetor yC from; one; or more fuel tanks, one ci which isillustrated at T1, and through an engine driven fuel pump P1 connectedwith the power shaft lil. During starting o -i the engine anelectrically driven auxiliary'pump;1:2 is operated, the motor thereforbeing shown at M2.

Duringl the starting of the engine it is primed through primer jets l5`from a conduit It, and when. engine fuel from the tank T1 is. used forpriming it is supplied from a branch i8. of the main.- fueli line 2?through a icy-pass valve BV. At that time the valve is opened byenergiaaticn of a solenoid S1.A g

At certain low temperatures a special auxiliary priming fuel; issupplied from a tank T2' through a priming fuel conduit 22,Y and. a4pump P3'. The pump P3 is driven by an electric. motor M3. A check valve'2.4 is provided to prevent reverse now of fuel from the conduit-s itand i2 into .the conduit 22.

The pump Phas a pressure regulating means in the form of arelief valveRV, the opening cf whichv is normallyopposed by a pair of' spings 26 and28. The pressure at which the pump operates is thus relatively high (60to 75 pounds per square inch). The pressure of the spring 28 may berelieved from `the relief valve RV by energizing a solenoid S2,whereupon the spring 26 only is operable and reduces the operatingpressure of the pump P3 to 30 or 40 pounds per square inch.

For controlling the solenoid S1, the motor M3 and solenond S2, relaysR1, R2 and R3 are provided, and these relays, together with solenoids S1and S2, pump P3, motor M3, by-pass valve BV, and relief valve RV,comprise a priming system PS for the engine. The relays are controlledby a thermostat T and a cam C3 mounted on a timer or cam shaft 3i! of asequence timer ST.

For driving the sequence timer, a, motor M is provided. The timer shaft30 also has cams C1, C2, C4, C5 and C6 thereon. The cam Cl controlsenergization of the starter S, the cam C2 controls energization of thebooster pump motor M2, solenoid S4 and motor M, the cam C4 controlsenergization of the starter meshing solenoid S3, the cam C5 controlsenergization of the ignition booster IB, and the cam C*3 controlsenergization of the signal light 32.

rlhese cams have lobes of such length that they perform their variousfunctions over time periods illustrated in Fig. 2. These periods arearbitrary, and may be varied somewhat in relation to each other, but ithas been found by experiment at all temperatures that the periodsillustrated in Fig. 2 are quite satisfactory, providing special primingfuels are used at low temperatures, such as those indicated in Fig. 3below 20 F.

The thermostat T, shown in detail in Fig. 4, comprises a bimetal coil 34or some equivalent temperature sensing element which is locatedpreferably adjacent the engine so as to be responsive to the temperatureambient to the engine. Location in the carburetor air induction systemis probably best. The bimetal coil 34 has a contact arm 36 engageablewith contact sectors 35, 38, 40 and 42 at the approximate temperaturesindicated on Figs. 1 and 4. The contact sectors 38, 40, and 42 areconnected with relays R3, R1 and R2, respectively, which relays eachinclude a holding switch 44 for retaining the relay energized after itsenergization is initiated by the thermostat and until such time as thecircuit to the coils of the relays is broken by a starting relay R. Athermostat cut-out switch 'I2 iS connected between the sector 35 of thethermostat T and ground and is adapted to be manually actuated.

With respect to the construction of the thermostat T the segments 42, 33and 40 are preferably adjustable as by mounting them by means of screws3l through slots 39. With such an arrangement the segment 38 can extendcounterclockwise as far as necessary since when the thermostat arm 36goes below --30 it stays on this contact. However, the clockwise end ofthe segment 38 must be accurately positioned to correspond to theposition of the arm 36 at -30. Similarly, the clockwise end of segment42 may be located anywhere, and the position of its counter-clockwiseend must be accurately located. Thus there are two points which must beset with considerable accuracy in the construction of the thermostat inorder to have it operate at the two specied temperatures, namely, 30 and20. It is also important that the clockwise end of segment 40 beaccurately located. This counterclockwise end, however, may overlap thesegment 42 to any extent, as there can be no circuit through the relaycoil R1 unless there is also one through the relay coil R2. In otherwords, after the arm 36 leaves the segment 42 it can still remain incontact with the segment 40 without effecting energization of the relaycoil R1. This permits of a comparatively simple arrangement ofthermostat segments which may be adjusted at three critical points,namely, 30", 20 and without having to adjust the length of the segment*I40, and this is made possible by the particular relay arrangement used.It is only when the arm 36 engages both segment 46 and segment 42 that-acircuit for the energization of relay R1 .becomes set up, and thecounter-clockwise projection of segment 40 beyond the counterclockwiseend of segment 42 is a matter of indifference. Segment 40 canaccordingly be made any convenient length, and an accurate machining jobis dispensed with.

The arm 36 may be provided with contact iingers 35H, 315a and lilla forproper engagement with the various segments 35, 30 and 42, and 40. Thebimetal element 34 may have one of its ends anchored to the arm 36 as byrivets 33, and its other end anchored to a stationary post 3l. Thispost, as well as the contact segments, are mounted on a suitable base 29of insulating material.

The cam shaft 36 of the sequential timer is normally rotatedcounter-clockwise, as by a spring 45, so that a stop arm 48 carried bythe shaft engages a stationary stop pin 50. The shaft is rotated in theopposite direction by the timer motor Mthrough driving and driven clutchdiscs 52 and 54. The discs are meshed by energization of a solenoid S4,the solenoid being energized whenever the motor M is energized anddeenergized when the motor is deenergized.

A starting push-button 53 is provided as an initiating control for thesequence timer, and for energizing a starting relay R, shown in itsnormal or unenergized position. The connections to the relay include aholding circuit which will here- .after be more fully described whendescribing the operation of the starting system. The timing period canbe terminated at any time by a stop push button at 58 which breaks thecircuit 'to the motor M and declutches the disc 52 from the disc 54 sothat the cam shaft 30 may return to the initial position shown in Fig.l. The current may be supplied from any suitable source, such as abattery B through a master switch 60.

For automatically breaking the circuit of the relay R a tachometerswitch TS is provided. This switch closes at about 800 R. P. M. of theengine and eiects deenergization of the coil of the relay l'tv byopening the delay switch DS. The delay switch includes a temperatureresponsive element such as a bimetal bar 62 thereof which warps upwardlyby heat from a heater H. The heater is adjusted so that the delay switchoperates about ten seconds after closure of the tachometer switch. Thecurrent from the battery B through the contacts of the relay R issupplied to the various circuits of the cams on the cam shaft 36 by abrush 64 contacting the cam shaft to transmit current to the shaft andthrough the shaft to each cam. The various circuits are believed clearlyillustrated in Fig. 1 so that they will need no further descriptionexcept as referred to'in the operation of the system which follows:

From the above it will be evident that the starting system for engine Eincludes as major components starter S, ignition booster IB, auxiliarypumpV P2, and priming system PS, controlled jointly by sequence-timer STand thermostat` T.

Practical operation Assuming that the temperature ambient-tov the engineE is in the range of 20? to 100?, the thermostat T will be in thepositionillustrated in Fig. l. The engine may now be started by'clos.-ing the master switch 60 and then pressing on the starting button e toinitiate operation. of the sequential timer. The current from thebattery B reaches the starter switch and from there passes through thenormally closed stopswitch 58 to the motor M by wayv of wire59 and to'.the solenoid S4 by way of branch wire Bland returns to ground as in allcircuits of the system. This results in the motor M rotating andthesolenoid S4 engaging the clutch 52-54 so that-fthe cam shaft 30starts rotating clockwise.`

Current through the starter switch 561 also passes through wire 66,delay switch DS, bimetalv element t2 and relay R, returning by wayofthev ground. This closes the starting relay R sothat current from themaster switch `60 is supplied through wires tl and 'li and the contacts600i the relay R to the timer switch brush Bil-byway of wire lil.Current is supplied from the-master switch S to the coils of the relaysR2 and R3iby wires 6l and tt. R3 is open at contact 38 ofthe-thermostat, but the circuit for the coil of relay R2 is closed atcontact 42, from which the current iicwsfthrough contact arm 3S, contact35, and to ground through thermostat cut-out switch l2 which is normallyclosed.

l Energization of the relay R2 depresses the bridging contact thereoffrom the position show-n in Fig. l so that current from wirev 68 issupplied to relay R1 and returns through theelement's'll, 35, 35 and i2to ground. This operation. of relay R2 prevents energization of themotor M3 for the auxiliary fuel pump P3 and sets up a circuit for thepriming solenoid S1 through wires 14`and16. The wire 'le is connectedwith thecontact wiper for the cam C3 so that the solenoid S1 isenergized only when the cam C3 lreaches the proper position (illustratedin Fig. 2 as twenty-live secends after the beginning of the startingcycle).

.The cams C1 and C2, it will beV noted, arein position to Contact theirwipersat theA beginning of the starting cycle. Accordingly, the currentthrough the relay R and the brush 64 Vpasses through wires I8 and 80 tothe starteriS. and the booster pump motor M2, respectively,forenergizing them. Current also ilows through wires 80 and S3 toenergize motor M and 'solenoid S4. This results in initiation ofrotation of camshaft 30, moving arm 48 away from stop 50. Thus in thetemperature range of 20 to 100, the starting cycle involves thefollowing steps:

The booster pump P2-andvthe starters vare energized at the beginning ofthe starting cycle. Priming is accomplished by energizing the boosterpump and the solenoid S1 for opening the by-pass valve BV so that astheengine is rotating `it will beprimed with engine fuel from the-tank`T1 through the conduit I6 to the priming jets I 5. The priming startstwenty-uve seconds after-'the beginning of the starting cycle. Fivesecond's'later the ignition booster IB is energized througha- Wire 82Vfrom cam C5, and the starter ismeshed with The circuit for the'coil ofrelay' cams C5, C1 and C4, respectively, passing their cam wipers.

It should here be mentioned that the start button 56 need not be held inall during the starting cycle. Instead, a holding circuit for the relayR is set-up when the relay is in the operated position. This holdingcircuit may be traced from the vmaster switch 60 through wires El and1I, the contact v6i) of the relay, the wire 10, the brush 64, .thesequence motor shaft 30, the cam C2, the wires 60, 63 and 59, the stopswitch 58, the wire 66, and the delay switch DS, together with itsbimetal bar 62, to one side of the coil of the relay R., the other sidebeing grounded. Thus the holding circuit is through the stop switch 58so vthat Whenever it is opened the holding circuitis broken.

The-engine should now be started, but if it has not. `or if, for anyreason, the operator wishes to stop the starting cycle, the stop button58 may be momentarily depressed, which breaks the holding circuit forrelay R, thus permitting the cam shaft30 to return to its initialposition for an, other start.

If the .enginezdoes not start, the motor `M .continues to rotate, and atH0 seconds the cam C6 engages its .cam wiper for energizing the signal32 to Warn the pilot that the starting cycle is about completed and itis time for him to change his carburetor mixture control from autorichto autolean At theend of seconds, the priming circuit is broken at thecam C3 so that current is no longer supplied to the solenoid S1. At thesame time the circuit to signal light 32 is broken by cam C, whilecircuits are broken by cam C2 which deenergize booster pump motor M2,motor M, and solenoid Si. The energization of solenoid S4 is eiective torelease cam shaft 30 from motor M so that it can return to its initialposition, with arm 48 against stop 50, under the influence. of spring68.

If the engine does start and reach a speed of 800 R. P. M., heater I-Iis energized by tachometer switch TS, and if the engine speed ismaintained for l0 seconds, the circuit to relay R is interruptedbyoperation of delay switch DS, putting the entiresystem out ofoperation. In this case light 32 is never energized.

After the starting cycle is initiated by depression of the startingbutton 56 it may be desirable to deenergize the circuit through thethermostat T to prevent a shift in the thermostat to a different rangecausing a lock-in of another relay in additionY to those initiallyenergized. They, of course, are held by their holding switches 44 sothat .current is no longer needed from the thermostat. This isaccomplished by manually opening the thermostat cut-out switch l2. Thisalso prevents any vibration caused by the starting of one engine on -amulti-engine aircraft from ai'- fecting the thermostat of another enginewhen its contact arm 36 is adjacent the position ci change from onetemperature rangeto another. This switch operates independently of thestartingswitch. If the pilot or operator of the system does not want tocut off the thermostat T he does not open the switch '12, and thethermostat remains operative in the circuit so as to respond to anychange in temperature conditions which might occur, for instance,between a false or attempted start and a second start. The false startmay have raised the temperature of the engine somewhat so as to positionthe thermostat ina different temperature range.

Irl-'the event that the temperaturer isat'or'above 100, the priming ofthe engine during starting is unnecessary. This is taken care of by thecontact sector 42 only being in electrical engagement with the contactorarm 3S so that onlyk the relay R2 is energized. The relay R2, whenenergized, cannot then energize the relay R1 because there is no circuitfrom the lower end of the coil of relay Rl through the contact sector40. Accordingly, the only element of the priming mechanism which isenergized is the booster pump motor M2 through the cam C2 so that a fuelsupply is provided during the starting period and until the engine hasattained suilicient speed for the main fuel pump P1 to efficientlysupply the requirements of the engine.

If the temperature range is between 30 and 20 the contactor arm 35 isfree of all sectors of the thermostat, with the possible exception ofsector 4B. However, the relay R1 can be energized only when the switchof the relay R2 is closed against the lower contacts thereof in additionto the circuit established across the arm 3; and the sector 40.Therefore, none of the relays R1, R2 and R3 is energized, and thisresults in the priming circuit from the wire 16 passing through thebridging contact of the relay R2 in its upper position, and a wire Si)to the motor M3 which drives the auxiliary primary fuel pump P3. Thepump will accordingly pump priming fuel from the tank T2 through theconduits 22 and i5 and the check Valve 24 to the priming jets of theengine, thus providing a more volatile fuel for easier starting at thistemperature.

The solenoid S2 will also be energized at this time because the bridgingcontact of the relay R3 remains in its raised position and, therefore,current from the wire 16 can flow to the solenoid S2 by way of wires 'iland l. rlhis compresses the spring 28 so that only the spring 23 opposesopening of the relief valve, and the spring 2S may have an effectivepressure of 30 to 4G pounds, which is indicated as Low Pressure in Fig.3. ln other respects the timing cycle is the same, that is, the boosterpump P2 is operated its usual length of time, the ignition booster andthe starter meshing circuits are energized their usual length of time,and priming is had over the usual time period. The signal 32 also lightsduring its usual last ten seconds of the starting cycle.

In the event that temperature is below 30", it is desirable to avoidenergizing the solenoid S2 so that both springs 26 and 28 can be imposedon the relief valve RV to cause the pump P3 to operate at high pressure,as indicated in Fig. 3 (.60 to 75 pounds per square inch) This isaccomplished by the Contact segment 3s being engaged by the contactorarm 36 of the thermostat T so that the relay R3 is energized to open thecircuit for the solenoid S2. In respects other than high pressure forthe priming fuel from the tank "I2 rather than low pressure, thestarting cycle in this case is the same as when the temperature range isbetween 30 and 20. I

After the starting cycle has been completed, and during which time anyone of the starting sequences may have been performed, depending uponthe position of the thermostat T, the master switch Sii can be manuallyopened and left in the open position until such time as the startingsystem is to again be used.

From the foregoing specification it will be obvious that 1 have providedan automatic starting system for internal combustion engines wherein thebasic control unit is a sequence switch controlled as to initiation by astarting switch. 'I'he starting cycle can be stopped immediately at anydesired time, and the sequence switch will be automatically reset to thestarting position for the cycle. Ten seconds after the engine is ringregularly the relay R is deenergized to shut down the starting mechanismand return the sequence switch to proper position for another startingcycle.

If the temperature ambient to the engine has been raised due to anincomplete start, the thermostat T may be in a position for anotherrange of temperature. No release of any of the relays R1, R2, and R3 cantake place, however, until the entire starting system is returned to itsinoperative condition, due to the eiiect of holding contacts 44.

Each starting cycle is initiated in a very simple manner by a momentarydepression of the starting button 5a to close the starting circuit. Theswitch '.'2 can thereafter be opened if desired to prevent vibrationfrom causing improper operation of the relays R1, R2 and R3 after theyare initially operated in accordance with the position of the thermostatat the time of starting. The operated relays are thereafter held in bytheir own holding switches to the exclusion of the remaining relay orrelays, as the case may be.

Some changes may be made in the construction and arrangement of theparts of my starting system without departing from the real spirit andpurpose of my invention, and it is my intention to cover by my claimsany modified forms of structure or use of mechanical equivalents whichmay be reasonably included within their scope.

I claim as my invention:

1. A starting system, for an internal combustion engine having primingmeans and fuel supply means, comprising temperature responsive controlmeans, means for causing variations in characteristics of the fuelsupplied to said priming means, means connecting said second named meansin controlled relation to said temperature responsive means for initialactuation in accordance with the response thereof, and means preventingsubsequent change in the response of said control means from furtheraiecting said second named means.

2. A starting system, for an internal combustion engine having primingmeans, comprising temperature responsive control means, means forpreventing operation of said priming means, means connecting said secondnamed means in controlled relation to said temperature responsive meansfor initial actuation during periods when the temperature exceeds aselected value, and means preventing subsequent change in the responseof said control means from altering the condition of actuation of saidsecond named means.

3. A starting system for an internal combustion engine having primingmeans, a source of priming fuel, and means for maintaining at a selectedupper value the pressure at which said fuel is supplied from saidsource, said system comprising temperature responsive control means;means for disabling said pressure maintaining means; and meansconnecting said disabling means in controlled relation to saidtemperature responsive means for actuation when the temperature is abovea selected value.

4. A starting system for an internal combustion engine having primingmeans, a source of priming fuel at a rst selected pressure, and meansfor reducing to a second selected value the pressure at which said fuelis supplied from said source, said system comprising for operating saidpressure reducing means, :temperature responsive control means, andmeans connecting said operating means in controlled rela-tion .to saidtemperature responsive-.means so that said priming means is suppliedwith said fuel at` said high pressure when the temperature is below acertain value and at said reduced pressure when the temperature isabovesaid value. A

5. A starting system, for van internal combustion engine. havingprimingmeans and fuel supply means, comprising temperature responsivecontrol means, means for determining characteristics of the fuelsupplied to said priming means, means connecting said second named meanstosaid temperature responsive means for actuation in accordance with theresponse thereof, and means for preventing subsequent change in saidresponse for causing change in the previously determined characteristicsof fuel.

6. A starting system for an internal combustion engine having primingmeans, a source of priming fuel at high pressure, and means for reducingthe pressure at which said fuel is supplied from said source, saidsystem comprising means for operating said pressure reducing means,temperature responsive control means, means connecting said furthermeans in controlled relation to said temperature responsive means sothat said priming means is supplied with said fuel at said high pressurewhen the temperature is below a rst selected value, and at said reducedpressure when the temperature is within a selected range; means forpreventing operation of said priming means; and means a connecting saidlast named means in controlled relation to said temperature responsivemeans fo-r actuation during periods when the temperature is above asecond selected value.

7. A starting system for aninternal combustion engine having primingmeans, sources of engine fuel and priming fuel at selected pressures,selective means for supplying fuel to said priming means from either ofsaid sources, and means for reducing the pressure at which said primingfuel is supplied from the source thereof, said system comprisingselective means for operating said pressure reducing means, temperatureresponsive control means, and means connecting said selective means incontrolled relation to said temperature responsive means so that saidpriming means is supplied with said engine fuel during periods when thetemperature is within a first selected range, with said priming fuel atreduced pressure during periods when the temperature is within a secondselected range, and With said priming fuel at said selected pressureduring periods when the temperature is below a selected value.

8. A starting system for an internal combustion engine having primingmeans, sources of engine fuel and priming fuel at selected pressures;selective means for supplying fuel to said priming means from either ofsaid sources, means for preventing operation of said priming means, andmeans for reducing the pressure at which said priming fuel is suppliedfrom the source thereof, said system comprising means for operatingpressure reducing means, temperature responsive'control means, and meansconnecting said operating means and said third named means in controlledrelation to said tempera-ture responsive means, so that said primingmeans vis prevented from operating during periods when the temperatureis above a, rst selected value, 'and is supplied with said engine fuelduring periods when Ythe temperaturer is within a first selected range,with said priming fuel 'at reduced pressure during periods when thetemperature is within a second selected range, and with said-primingfuel at said'selected pressure during periods when the temperature isbelow a second selected Value.

9. A starting system for an internal combustion engine Vhaving primingmeans, means maintaining a supply of engine fuel at a selectedpressureya source of priming fuel, pump means for supplying priming fuelfrom said source at a selected `pressure, firstmotor means operable toactuate said pump means, means for conducting said engine fuel and saidpriming fuel to said priming means-normally closed valve means forpreventing said engine fuel from -reaching said priming means, andsecond motor means operable to open said Valve means, said systemcomprising rst and second relay means for causing and interruptingoperation of said first and second motor means respectively, temperatureresponsive relay control means, means connecting said relay means incontrolled relation to said temperature responsive means so that saidrst motor means is operated during periods when the temperature is belowa selected value d said second motor means is operating during periodswhen the temperature is within a selected range, and meansinterconnecting said relay means so that said second motor means canopen said valve only when actuation of said pump means by operation ofsaid first motor means is interrupted.

10. A starting system for an internal combustion engine having primingmeans, a source of priming fuel, pump means for supplying said primingfuel to said priming means at a first selected pressure, rst motor meansoperable to actuate said pump means, relief valve means for reducing toa second selected value the pressure at which said priming fuel issupplied by lsaid pump means, and second motor means operable to disablesaid relief valve means, said system comprising relay means for causingand interrupting operation of said motor means, temperature responsiverelay control means, and means connecting said relay means in controlledrelation to said temperature responsive means so that said first motormeans actuates said pump during periods when the temperature is below aselected value and said second motor means di:- ables said relief valveduring periods when said temperature is Within a selected range.

11. A starting system for an internal combustion engine having primingmeans, means maintaining a supply of engine fuel at a selected pressure,a source of priming fuel, pump means for supplying priming fuel at aselected normal pressure, first motor means operable to actuate saidpump means, relief valve means for reducing to a second selected valuethe pressure at which said priming fuel is supplied by said pump means,second motor means operable to actuate relief valve means, means forconducting said priming fuel and said engine fuel to said priming means,normally closed valve means for preventing said engine fuel fromreaching said priming means, and third, motor means operable to opensaid normally closed Valve means, said system com-r prising: first,second and third relay means for causing and interrupting operation ofsaid rst, second and third motor means; temperature responsive relaycontrol means; and means con- 11 necting said relay mea-ns in controlledrelation to said temperature responsive means so that no fuel passes tosaid priming means during periods when the temperature exceeds a rstselected value, so that engine fuel passes to said priming means duringperiods when the temperature is in a first selected range, so thatpriming fuel at said reduced pressure passes to said priming meansduring periods when the temperature is in a second selected range, andso that priming fuel at said normal pressure passes to said primingmeans when said temperature is below a second selected value.

MALCOLM P. ODELL.

REFERENCES CITED The following references are of record in the le ofthis patent:

Number UNITED STATES PATENTS Name Date Van Horn Oct. 16 1923 Federle May12, 1925 Stokes Jan. 1, 1929 Ide Mar. 19, 1929 Ross Jan. 21, 1930Fitzsimmons Aug. 23, 1932 Igarashi Sept. 24, 1935 Flamini Nov. 9, 1937Vroom Dec, 13, 1938 Alexander Apr. 17, 1945 Ovens Aug. 15, 1950

